Method

In large bowl, whisk together eggs, butter­milk, coffee and oil. Whisk in chocolate hazelnut spread until smooth. Whisk in flour mixture in 3 additions until smooth. Divide between prepared pans.

Bake until cake tester inserted in centres of cakes comes out clean, about 35 minutes. Let cool in pans for 10 minutes. Invert onto rack; peel off paper. Let cool completely. (Make-ahead: Wrap the cakes in plastic wrap and freeze for up to one month. Thaw at room temperature.)

Chocolate Hazelnut Frosting: In stand mixer with paddle attachment, beat butter on medium-high speed until fluffy, 2 to 3 minutes. Reduce speed to low; beat in icing sugar, in 3 additions, for about 2 minutes. Increase speed to medium; beat until fluffy, 4 minutes. Beat in chocolate hazelnut spread, vanilla and salt on medium speed until light and fluffy, about 1 minute. Beat in milk until smooth and spreadable.

Cut each cake in half horizontally to make 4 layers. Place 1 layer, cut side up, on cake plate; spread about one-quarter of the Chocolate Hazelnut Frosting over top. Top with second layer, cut side down; spread about one-quarter of the Chocolate Hazelnut Frosting over top. Repeat with remaining cake and Chocolate Hazelnut Frosting. Arrange 3D Chocolate Ginger Christmas Trees on top of and around cake (if using).